<form method="post" action="<?php echo $_SERVER['HTTP_ORIGIN'] ?>/php2/com/index.php">
用户名：<input type="text" name="username"><br/>
密码：<input type="text" name="password"><br/>

<input type="submit"><br/>

</form>

<?php 
//echo __FILE__;

$arr = array(4,5,6=>90);

foreach ($arr as $a=>$b){
    echo $a.'=='.$b;
}

$conn = new mysqli('localhost','root','root','php')



?>